I have experimented on Ubuntu trying IPV6 tunneling through my NAT router and ipv4 connection using miredo. It works but for security reasons it is necessary to make the firewall IPV6 aware. This is easily done in Ubuntu by changing a line in the config file but is it possible in Puppy Firewall?

I have looked at the project page but it no longer exists so it must be an old firewall.

Well, the firewall is just iptables, used by almost every linux. Likely that supports IPV6. The script invoking it is /etc/rc.d/rc.firewall, which you would probably have to modify and rerun. There are some parameters in there to change characteristics (e.g. logging) but I don't see anything about ipv6. It does access the directory /proc/sys/net/ipv4 in several places, and there is no /proc/sys/net/ipv6, so some work clearly needs to be done.

Woops, if you google iptables with ipv6 it becomes clear that iptables is for ipv4 and another program, ip6tables, is for ipv6.

Seems like you should be able to find something in the Ubuntu repositories if you are running lupu.